Characterization of newly synthesized cycloalkanespiro-5-hydantoin derivatives using liquid chromatography

Hromatografsko ponašanje i lipofilnost 21 novosintetisanog 3-(4- supstituisani benzil)cikloalkanspiro-5-hidantoina proučavana je u uslovima tečne hromatografije na obrnutim fazama. Hromatografsko ponašanje ispitivano je primenom tečne hromatografije na tankom sloju i tečne hromatografije pod visokim pritiskom. Kao nepokretna faza primenjen je hemijski modifikovani silika gel sa kovalentno vezanim C-18 grupama. Kao pokretne faze korišćene su dvokomponentne smeše vode i organskog rastvarača u različitim zapreminskim odnosima. U hromatografiji na tankom sloju pokretne faze su sadržale jedan od sledećih organskih rastvarača: etanol, n-propanol, i-propanol, t-butanol, acetonitril, aceton, tetrahidrofuran ili 1,4-dioksan, dok je u hromatografiji pod visokim pritiskom kao pokretna faza korišćena smeša vode i acetonitrila. Na osnovu rezultata ispitivanja diskutovan je uticaj prirode organskog rastvarača u pokretnoj fazi, uticaj strukture spirohidantoina, kao i uticaj sadržaja organskog rastvarača na hromatografsko ponašanje ispitivanih jedinjenja. Linearna zavisnost RM vrednosti od zapreminskog udela organskog rastvarača u pokretnoj fazi utvrđena je za sva ispitivana jedinjenja. Na taj način omogućeno je izračunavanje hromatografskog parametara lipofilnosti (RM0, odnosno log kw). Izračunati hromatografski parametri lipofilnosti su upoređeni sa računskim parametrima lipofilnosti (log P) primenom linearne regresione analize i uspostavljene su linearne zavisnosti. Podeoni koeficijenti log P za sve ispitivane spirohidantoine određeni su i indirektno uz pomoć referntnih jedinjenja, odnosno na osnovu kalibracionih modela. LSER modelovanje primenjeno kako bi se ustanovilo koje interakcije dovode do raspodele u samim hromatografskim sitemima, odnosno raspodele između pokretne i nepokretne faze. Pored identifikacije interakcija, LSER modelovanje je primenjeno za utvrđivanje vrste, kao i za određivanje jačine hemijskih interakcija. QSRR analiza je primenjena za pronalaženje matematičkih modela kojim se opisuje veza između hromatografskih parametara lipofilnosti i strukture novosintetisanih derivata spirohidantoina. Do odgovarajućih QSRR modela došlo se primenom metode višestruke linearne regresije (MLR). Sposobnost predviđanja svakog modela je definisana internim validacionim koeficijentom. Pravilo Lipinskog je primenjeno sa ciljem da se proveri da li ispitivani spirohidantoini imaju dobru (teorijsku) oralnu biodostupnost. Uticaj organskog rastvarača u pokretnoj fazi, kao i uticaj supstituenta na hromatografsku lipofilnost procenjen je primenom metoda multivarijantne analize, hijerarhijskom klaster analizom (HCA) i analizom glavnih komponenata (PCA). Ove metode omogućavaju grupisanje ispitivanih derivata spirohidantoina, kao i primenjenih pokretnih faza prema njihovoj polarnosti. Primenom ove dve metode proučavana je i povezanost hromatografskih parametara lipofilnosti i potencijalne biološke aktivnosti spirohidantoina.The chromatographic behavior and lipophilicity of 21 newly synthesized 3-(4- substituted benzyl)cycloalkanespiro-5-hydantoins were studied in reversedphase liquid chromatography conditions. Chromatographic behavior was analyzed by using thin-layer liquid chromatography and high-performance liquid chromatography. Chemically modified silica gel with covalently bonded C-18 groups was used as the stationary phase. Two-component mixtures of water and organic solvent in different volume ratios were used as mobile phases. In thin-layer chromatography, the mobile phases contained one of the following organic solvents: ethanol, n-propanol, i-propanol, t-butanol, acetonitrile, acetone, tetrahydrofuran, or 1,4-dioxane, while in highperformance liquid chromatography the mixture of water and acetonitrile was used as mobile phase. Based on the test results, the influence of the nature of the organic solvent in the mobile phase, the influence of the structure of spirohydantoin, as well as the influence of the content of the organic solvent on the chromatographic behavior of the tested compounds was analyzed. The linear dependence of the RM value on the volume fraction of organic solvent in the mobile phase was determined for all tested compounds. In this way, it was possible to calculate the chromatographic parameters of lipophilicity (RM0, ie log kw). The calculated chromatographic parameters of lipophilicity were compared with the calculated parameters of lipophilicity (log P) using linear regression analysis and linear dependences were established. The partition coefficients log P for all tested spirohydantoins were determined indirectly, as well, with the help of reference compounds, based on calibration models. LSER modeling was used to determine which interactions lead to the partition in the chromatographic systems, that is the partition between the mobile and stationary phases. In addition to identifying interactions, LSER modeling was used to determine the type as well as the strength of chemical interactions. QSRR analysis was applied to find mathematical models for describing the relationship between chromatographic lipophilicity parameters and the structure of newly synthesized spirohydantoin derivatives. The corresponding QSRR models were obtained by using the multiple linear regression (MLR) method. The predictability of each model is defined by an internal validation coefficient. Lipinski's rule was applied to verify whether the tested spirohydantoins have good (theoretical) oral bioavailability. The influence of the organic solvent in the mobile phase, as well as the influence of the substituent on chromatographic lipophilicity, was assessed using multivariate analysis methods, hierarchical cluster analysis (HCA), and principal components analysis (PCA). These methods group the tested spirohydantoin derivatives, as well as the applied mobile phases based on their polarity. The relationship between chromatographic parameters of lipophilicity and the potential biological activity of spirohydantoin was analyzed using these two methods